MethodPreheat oven to 200 o C/ 400 o F. Place all ingredients in a mixing bowl & blend thoroughly. Press the mixture into the bottom of 8 inch springform pan. Bake for about 6 mins. Cool before filing.

For fillingPreheat oven to 350 o F/ 180 o C. Melt the chocolate on top of a double boiler or (or microwave). Meanwhile beat together the cream cheese & sugar ; beat in one egg at a time, mixing thoroughly after each addition.Stir in the melted chocolate, then add liqueur, butter & sour cream. Blend well. Pour the mixture into the prepared crust & bake for 45-50 mins, till centre is firm to touch but slightly wobbly when shaken. Turn off the heat & prop the oven door open. Leave cake in oven for 1 hour, let cake cool to room temperature, then chill.

Source: Wilton springpan recipes

Note: The cheesecake tastes equally good even if u skip the sour cream & the liqueur.